How to control animation speed and direction in BGE
I could not find any info and this, so since i figured it out, i would post the answer. I used logic block and a python scrip. The example is not for a follow path, but just a simple cube animation.

The game goes as follows:
Press space key to start animation, press again to stop the action.
Press the F key to speed up the animation, and press the S get to go slower.

I included some images.

import bge


def main():

# max frame of animation
maxFrame = 100

cont = bge.logic.getCurrentController()
own = cont.owner

frameAct = cont.actuators['Frame']

currentFrame = own.get(frameAct.propName)

# limit speed to between 1 and 10
speed = own['speed']
speed = max(1,speed)
speed = min(10,speed)

speedInc = (0.10*speed)

currentFrame = currentFrame + speedInc

if currentFrame &gt; maxFrame:
    currentFrame = 1

frameAct.value = str(currentFrame)
cont.activate(frameAct)


main()